A typical vane-type camshaft phaser for changing the phase relationship between a crankshaft and a camshaft of an internal combustion engine generally comprises a plurality of outwardly-extending vanes on a rotor interspersed with a plurality of inwardly-extending lobes on a stator, forming alternating advance and retard chambers between the vanes and lobes. Engine oil is selectively supplied to one of the advance and retard chambers and vented from the other of the advance and retard chambers in order to rotate the rotor within the stator and thereby change the phase relationship between an engine camshaft and an engine crankshaft. Camshaft phasers also commonly include an intermediate lock pin which selectively prevents relative rotation between the rotor and the stator at an angular position that is intermediate of a full advance and a full retard position. The intermediate lock pin is engaged and disengaged by venting oil from the intermediate lock pin and by supplying pressurized oil to the intermediate lock pin respectively.
Some camshaft phasers use a phasing oil control valve to selectively supply and vent oil to and from the advance chambers and the retard chambers in order to control the phasing function of the camshaft phaser while a separate lock pin oil control valve is used to selectively supply and vent oil to and from the lock pin in order to control the lock pin function of the camshaft phaser, thereby allowing the phasing function and the lock pin function to be controlled independently of each other. U.S. patent application Ser. No. 13/667,127 to Lichti et al., the disclosure of which is incorporated herein by reference in its entirety, teaches a camshaft phaser which uses a phasing oil control valve that is external to the camshaft phaser and a lock pin oil control valve that is located within the camshaft phaser. Lichti et al. teaches that this arrangement allows for a more axially compact camshaft bearing compared to a camshaft phaser in which both the phasing oil control valve and the lock pin oil control valve are located external to the camshaft phaser. While the camshaft phaser of Lichti et al. may effectively allow for a more axial compact camshaft bearing, a separate dedicated oil supply is needed to supply oil to the lock pin oil control valve that is located within the camshaft phaser.
What is needed is camshaft phaser which minimizes or eliminates one or more the shortcomings as set forth above.